import math
x1, y1, x2, y2 = map(float, input().split())
x = abs(x1 - x2)
y = abs(y1 - y2)
ans = math.sqrt(x**2 + y**2)
print('{:.5f}'.format(ans)) import math math x1, y1, x2, y2 = map(float, input().split()) x1 map(float, input().split()) map float input().split() ().split () input split y1 x2 y2 x = abs(x1 - x2) x abs(x1 - x2) abs x1 - x2 x1 x2 y = abs(y1 - y2) y abs(y1 - y2) abs y1 - y2 y1 y2 ans = math.sqrt(x**2 + y**2) ans math.sqrt(x**2 + y**2) math.sqrt math sqrt x**2 + y**2 x**2 x 2 y**2 y 2 print('{:.5f}'.format(ans)) print '{:.5f}'.format(ans) '{:.5f}'.format '{:.5f}' format ans y2 = map(float, input().split()) map(float, input().split()) y2 x = abs(x1 - x2) abs(x1 - x2) x y1, x2, y2 = map(float, input().split()) map(float, input().split()) y1 x1, y1, x2, y2 = map(float, input().split()) map(float, input().split()) x1 x2, y2 = map(float, input().split()) map(float, input().split()) x2 y = abs(y1 - y2) abs(y1 - y2) y ans = math.sqrt(x**2 + y**2) math.sqrt(x**2 + y**2) ans
import math
x1, y1, x2, y2 = map(float, input().split())
x = abs(x1 - x2)
y = abs(y1 - y2)
ans = math.sqrt(x**2 + y**2)
print('{:.5f}'.format(ans))
